The Cardiovascular Effects of Thoracic Bolus Epidural Injection of Lidocaine, Morphine and Fentanyl during Sevoflurane General Anesthesia

Background: Sevoflurane is an inhalational anesthetic that produces rapid induction, emergence and little cardiovascular depression. Elevated sympathetic activity during surgery produces undesirable effects on the cardiovascular system, such as hypertension, tachycardia or arrhythmias. So combined general and epidural anesthesia have been used recently for the operation, especially the abdominal surgery. This study was performed to evaluate the cardiovascular effects of thoracic epidural anesthesia during sevoflurane general anesthesia. Methods: Forty patients of ASA class 1-2 undergoing elective subtotal gastrectomy were divided into 5 groups. Thoracic epidural bolus injection was administered via an epidural catheter during sevoflurane general anesthesia in a double-blind random manner: Group 1; normal saline (N/S) 10 ml (placebo), Group 2; morphine 0.1 mg/kg mixed with N/S in 10 ml, Group 3; fentanyl 1 mcg/kg mixed with N/S in 10 ml, Group 4; 1% lidocaine 10 ml, and Group 5; 1% lidocaine 10 ml mixed with morphine 0.1 mg/kg and fentanyl 1 mcg/kg. Systolic and diastolic blood pressures, pulse rates, peripheral oxygen saturation levels (Sp) and end-tidal carbon dioxide partial pressures (ETC) were measured every 5 minutes. Results: Systolic and diastolic blood pressures were significantly reduced from 10 minutes after epidural bolus injection in groups 4 and 5, but these decreases in blood pressure were not severe enough to require treatment in either group. Pulse rates were significantly decreased from 10 minutes after injection in groups 3, 4, and 5, but these decreases in pulse rate were not so severe enough to require treatment in 3 groups. Sp and ETC were stable, and arrhythmia was not observed. Conclusions: The thoracic epidural injection of 1% lidocaine mixed with morphine 0.1 mg/kg and fentanyl 1 mcg/kg can be safely used during sevoflurane anesthesia without severe cardiovascular complications during upper abdominal surgery in ASA 1-2 patients.